The present invention relates generally to an electrical connection box having a casing and a cover engageable with the casing which are interlocked with each other, and more particularly, to such an electrical connection box disposed in a wiring connection, junction or branch area of wire harness or the like in connection with various kinds of electrical devices or equipments in a vehicle or the like so that the cover and the casing can be assembled together, regardless of whether a watertight packing is interposed therebetween.
An electrical connection box has been employed in variety of electric wiring or circuits in order to connect or branch wire harness or the like which leads to various kinds of electric equipments in an automobile vehicle or the like. Such an electrical connection box is exemplified in FIG. 3, which is of a rectangular profile. This kind of connection box comprises an assembly of a lower casing 1 and an upper cover 2, which are produced by injection molding processes of resin, such as polypropylene, nylon or polybutyl terephthalate, with use of a metal mold.
The casing 1 has a side wall or plate 1b on a peripheral zone of a bottom wall 1a, whereas the cover 2 has a side wall or plate 2b on a peripheral zone of a top wall 2a. Female locking elements 10 in a pair are provided on the side wall 1b of the casing 1 and male locking elements 20 engageable with the female locking elements 10 are provided on the side wall 2b of the cover 2. The female and male locking elements 10, 20 are interlocked with each other, so that the casing 1 and the cover 2 are integrally assembled in an interlocking position so as to define an enclosure of electric devices, such as fuses 50 or relays 60.
Referring to FIG. 4, a structure of the female and male locking elements 10, 20 are illustrated as an example. The female locking element 10 is provided on an upper outside surface of the side wall 1b of the casing 1, which element 10 comprises a bottom wall 11 and a side wall 12 generally formed in a L-shaped cross-section. A base end of the bottom wall 11 is secured to the side wall 1b, and a hook-shaped locking pawl 13 is disposed to protrude inwardly at an upper end of the side wall 12.
The male locking element 20 is formed on a lower outside surface of the side wall 2b of the cover 2, the element 20 comprising a flexible part 21 in a form of the letter xe2x80x9cVxe2x80x9d in its cross-section so as to be insertable into the female locking element 10, and a joint portion 22 integrally extending to a base end of the flexible part 21 and supported by the side wall 2b of the cover 2. The flexible part 21 is provided at its outside end portion with a pressed or pinched part 23 used for deflecting or deforming the flexible part 21. A locking hole 24 is formed in a position of the flexible part 21 adjacent to the pressed part 23 so as to receive the locking pawl 13 of the female locking element 10.
The joint portion 22 is provided with a recess or groove 25 between the cover 2 and the base end of the flexible part 21, which recess has a width corresponding to a thickness of the side wall 1b of the casing 1. If the electrical connection box is to be used in an engine room or the like into which water or moisture may leak, waterproofness of the connection box is required, and therefore, the recess 25 is formed to have a substantial depth for containing a watertight packing 3 therein, as shown in FIGS. 4(c), (d). If such waterproofness is not required, the recess 25 is formed to have a relatively small dimension in depth so as to be merely engaged with the end edge of the casing 1, as shown in FIGS. 4(a), (b). Thus, different combinations of the casings and covers have to be prepared in accordance with their condition in use, i.e., in response to provision or omission of the packing 3.
In use of such a conventional connection box, the cover 2 with the male locking element 20 is placed on the casing 1 with the female locking element 10, so that the flexible part 21 is inserted into the female locking element 10 as the part 21 being deformed inwardly. At the time when the joint portion 22 or the packing 3 bears against the upper end edge of the side wall 1b of the casing 1, the locking pawl 13 of the female locking element 10 is inserted into the locking hole 24 of the male locking element 20, whereby the casing 1 and the cover 2 are integrally assembled in an interlocking position. If the cover 2 is to be disassembled from the casing 1, the pressed part 23 of the male locking element 20 is pressed inwardly to disengage the locking pawl 13 from the locking hole 24, so that the interlocking action of the casing 1 and the cover 2 is relieved.
With reference to FIG. 5, another structure of the female and male locking elements 30, 40 are exemplified. The female locking element 30 in a form of letter xe2x80x9cCxe2x80x9d or rectangular frame is provided on an outside surface of the side wall 1b of the casing 1 at a position slightly lower than the upper edge thereof, an inner surface of the element 30 being provided with a hook-shaped locking pawl 31 opposing to the outside surface of the side wall 1b. 
The male locking element 40 is formed on a lower outside surface of the side wall 2b of the cover 2, which element 40 comprises a flexible part 41 profiled in a form of upset xe2x80x9cUxe2x80x9d in its transverse cross-section to be inserted into the female locking element 30, and a joint portion 42 integrally extending from a bent portion of the flexible part 41 and supported by the side wall 2b of the cover 2. The flexible part 41 is provided at its outside end portion with a hook-shaped locking pawl 43 outwardly extending to be engaged with the locking pawl 31.
The joint portion 42 is provided with a recess or groove 44 between the cover 2 and the base end of the flexible part 41, which has a width corresponding to a thickness of the side wall 1b. If the electrical connection box is to be used in an engine room or the like into which water or moisture may leak, waterproofness of the connection box is required, and therefore, the recess 44 is formed to have a substantial depth for containing a watertight packing 3 therein, as shown in FIGS. 5(c), (d). If such waterproofness is not required, the recess 44 is formed to have a relatively small dimension in depth so as to be merely engaged with an end edge of the casing 1, as shown in FIGS. 5(a), (b). As is similar to the aforementioned type of structure, a particular structure of the casing 1 and cover 2 be predetermined in each of the conditions in use, which depends on provision of the packing 3.
In use of this connection box, the cover 2 with the male locking element 40 is placed on the casing 1 with the female locking element 30, and the joint portion 42 or the packing 3 abuts against the upper end edge of the side wall 1b. Simultaneously with the abutment, the locking pawls 43, 31a re engaged or latched with each other, so that the casing 1 and the cover 2 are integrally assembled in an interlocking position. When the cover 2 is disassembled from the casing 1, the outside of the male locking element 40 is urged inwardly until the locking pawl 43 can be disengaged from the locking pawl 31, thereby releasing the interlocking action therebetween.
Arrangements of those kinds of electrical connection boxes are disclosed in Japanese Patent Laid-Open Publication No.9-79221 or Japanese Utility-Model Laid Open Publication No.7-39226, in which a casing and a cover are securely interlocked without loose conditions occurring. Further, another type of electrical connection box is disclosed in Japanese Patent Laid-Open Publication No.9-151916 in which a cover is adapted to be engaged with a casing selectively in two levels without mismatching them in inappropriate interlocking positions.
In those conventional connection boxes, the specific locking pawl 13 is inserted into the counterpart locking hole 24; or otherwise, the specific locking pawl 31 is engaged with its counterpart locking pawl 43, whereby the cover 2 and the casing 1 can be integrally assembled in a desired interlocking position. It follows that the different casings 1 and/or covers 2 have to be prepared in accordance with the requirement or necessity of using the packing 3.
This, however, results in fabrication or modification of at least two types of metal molds for producing such different casings 1 and/or covers 2 in response to installation or elimination of the packing, since the casings 1 and covers 2 are produced by injection molding processes of resin with use of the metal molds. Such preparation of different types of molds and processes leads to an undesired increase of manufacturing costs for the connection boxes.
Although the electrical connection boxes are disclosed in Japanese Patent Laid-Open Publications Nos. 9-79221 and 9-151916 and Japanese Utility- Model Laid-Open Publication No. 7-39226, those publications do not disclose nor suggest any arrangement for assembling the casing and the cover in both of a condition in use of a packing and an unused condition thereof.
It is an object of the present invention to provide an electrical connection box, a casing and cover of which can be securely assembled, regardless of whether a packing is to be interposed therebetween.
The present invention provides an electrical connection box having a casing and a cover to be placed on the casing so as to allow the casing and the cover to be engaged with each other in an interlocking position, wherein one of the casing and the cover is provided with a locking pawl and the other thereof is provided with a first locking hole or pawl and a second locking hole or pawl; and wherein said first locking hole or pawl is adapted to be engaged with said locking pawl when a packing is interposed between said casing and said cover, and said second locking hole or pawl is adapted to be engaged with said locking pawl when the packing is not interposed between said casing and said cover.
From another aspect of the invention, the present invention provides an electrical connection box having a casing and a cover to be placed on the casing so as to allow the casing and the cover to be engaged with each other in an interlocking position, wherein one of the casing and the cover is provided with a locking hole and the other of said casing and said cover is provided with a first locking pawl and second locking pawl; and wherein said first locking pawl is adapted to be engaged with said locking hole when a packing is interposed between said casing and said cover, and said second locking pawl is adapted to be engaged with said locking hole when the packing is not interposed between said casing and said cover.
Preferably, the cover may be formed with a recess or groove which can be equipped with the packing therein and which is also adapted to be directly fit to a side wall of the casing in a case where the packing is not interposed between the casing and the cover.
According to the electrical connection box of the present invention, the casing and the cover can be integrally assembled in interlocking positions, regardless of whether the packing is provided therebetween.